Weight stack frame



FIG. 1 is a side elevational view of a weight stack frame showing ournew design, wherein the broken line showing of the weight stack andexercise machine is for illustrative purposes only and forms no part ofthe claimed design;

FIG. 2 is a rear perspective view of the weight stack frame;

FIG. 3 is a front view thereof; and,

FIG. 4 is a top plan view thereof.

The ornamental design for a weight stack frame, as shown.